如何使用php获取html文档中有id属性的节点

how to get reference of node where there is id attribute set from an entire HTML documents using php (domdocument)?

<div id='foo'>
lorem ipsum
</div>
<div id='bar'>
lorem ipsum
</div>
<div id="baf">
  <div id="alpha">
  lorem ipsum
  </div>
</div>

i want to get list of foo,bar,baf,alpha nodes. nodes can be arbitrarily existed.

You can just use str_get_html

$html = '<div id="foo">
lorem ipsum
</div>
<div id="bar">
lorem ipsum
</div>
<div id="baf">
  <div id="alpha">
  lorem ipsum
  </div>
</div>';

$html = str_get_html($html);
foreach ( $html->find("div") as $value ) {
    var_dump($value->id);
}

Output

string 'foo' (length=3)
string 'bar' (length=3)
string 'baf' (length=3)
string 'alpha' (length=5)